The 10mm Auto (10×25mm, Official C.I.P. Nomenclature: 10mm Auto) is a semi-automatic pistol cartridge developed by Jeff Cooper and introduced in 1983 with the Bren Ten pistol. It was initially produced by ammunitions manufacturer FFV Norma AB of Åmotfors, Sweden.
Although it was selected by the Federal Bureau of Investigation for use in the field following the 1986 F.B.I. Miami Shootout, their Firearms Training Unit "concluded that its recoil was excessive in terms of training for average agent/police officer competency of use and qualification", and the pistols that chambered it were too large for some small-handed individuals. These issues led to the creation and eventual adoption of a shortened version of the 10mm that would evolve into what is today the .40 S&W.
The 10mm never attained the mainstream success of its downgraded variant, the .40 Smith & Wesson, but there is still an enthusiastic group of supporters who often refer to the .40 S&W as the ".40 Short & Weak".
Read more about 10mm Auto: History, Cartridge Dimensions, Performance, Usage, Synonyms, Gallery